fixed adplug dual_opl2 emulation (stereo now works)

1 files changed, 63 insertions, 37 deletions

diff --git a/plugins/adplug/adplug/emuopl.cpp b/plugins/adplug/adplug/emuopl.cpp
index 0f751e16..43754c61 100644
--- a/plugins/adplug/adplug/emuopl.cpp
+++ b/plugins/adplug/adplug/emuopl.cpp
@@ -21,11 +21,16 @@
 
 #include "emuopl.h"
 
+#define likely(x)       __builtin_expect((x),1)
+#define unlikely(x)     __builtin_expect((x),0)
+
 CEmuopl::CEmuopl(int rate, bool bit16, bool usestereo)
   : use16bit(bit16), stereo(usestereo), mixbufSamples(0)
 {
   opl[0] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
   opl[1] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
+  mixbuf0 = 0;
+  mixbuf1 = 0;
 
   currType = TYPE_DUAL_OPL2;
 
@@ -36,10 +41,8 @@ CEmuopl::~CEmuopl()
 {
   OPLDestroy(opl[0]); OPLDestroy(opl[1]);
 
-  if(mixbufSamples) {
-    delete [] mixbuf0;
-    delete [] mixbuf1;
-  }
+  delete [] mixbuf0;
+  delete [] mixbuf1;
 }
 
 void CEmuopl::update(short *buf, int samples)
@@ -47,15 +50,22 @@ void CEmuopl::update(short *buf, int samples)
   int i;
 
   //ensure that our mix buffers are adequately sized
-  if(mixbufSamples < samples) {
-    if(mixbufSamples) { delete[] mixbuf0; delete[] mixbuf1; }
-    mixbufSamples = samples;
+  if(unlikely (mixbufSamples < samples)) {
 
+      if (mixbuf0) {
+          delete[] mixbuf0;
+          mixbuf0 = 0;
+      }
+      if (mixbuf1) {
+          delete[] mixbuf1;
+          mixbuf1 = 0;
+      }
     //*2 = make room for stereo, if we need it
     mixbuf0 = new short[samples*2]; 
     mixbuf1 = new short[samples*2];
   }
 
+  mixbufSamples = samples;
   //data should be rendered to outbuf
   //tempbuf should be used as a temporary buffer
   //if we are supposed to generate 16bit output,
@@ -65,10 +75,12 @@ void CEmuopl::update(short *buf, int samples)
   //and so it must point to a mixbuf instead--
   //it will be reduced to 8bit and put in "buf" later
   short *outbuf;
-  short *tempbuf=mixbuf0;
-  short *tempbuf2=mixbuf1;
-  if(use16bit) outbuf = buf;
-  else outbuf = mixbuf1;
+  if (likely (use16bit)) {
+      outbuf = buf;
+  }
+  else {
+      outbuf = mixbuf1;
+  }
   //...there is a potentially confusing situation where mixbuf1 can be aliased.
   //beware. it is a little loony.
 
@@ -82,11 +94,12 @@ void CEmuopl::update(short *buf, int samples)
 
     //if we are supposed to output stereo,
     //then we need to dup the mono channel
-    if(stereo)
-      for(i=samples-1;i>=0;i--) {
-	outbuf[i*2] = outbuf[i];
-	outbuf[i*2+1] = outbuf[i];
-      }
+    if(unlikely (stereo)) {
+        for(i=samples-1;i>=0;i--) {
+            outbuf[i*2] = outbuf[i];
+            outbuf[i*2+1] = outbuf[i];
+        }
+    }
     break;
 
   case TYPE_OPL3:	// unsupported
@@ -95,40 +108,53 @@ void CEmuopl::update(short *buf, int samples)
   case TYPE_DUAL_OPL2:
     //for dual opl2 mode:
     //render each chip to a different tempbuffer
-    YM3812UpdateOne(opl[0],tempbuf2,samples);
-    YM3812UpdateOne(opl[1],tempbuf,samples);
+    YM3812UpdateOne(opl[0],mixbuf1,samples);
+    YM3812UpdateOne(opl[1],mixbuf0,samples);
 
     //output stereo:
     //then we need to interleave the two buffers
-    if(stereo){
-      //first, spread tempbuf's samples across left channel
-      //left channel
-      for(i=0;i<samples;i++)
-	outbuf[i*2] = tempbuf2[i];
-      //next, insert the samples from tempbuf2 into right channel
-      for(i=0;i<samples;i++)
-	outbuf[i*2+1] = tempbuf[i];
-    } else
-      //output mono:
-      //then we need to mix the two buffers into buf
-      for(i=0;i<samples;i++)
-	outbuf[i] = (tempbuf[i]>>1) + (tempbuf2[i]>>1);
+    if(unlikely (stereo)){
+        //first, spread tempbuf's samples across left channel
+        for(i=0;i<samples;i++)
+            outbuf[i*2] = mixbuf1[i];
+        //next, insert the samples from tempbuf2 into right channel
+        for(i=0;i<samples;i++)
+            outbuf[i*2+1] = mixbuf0[i];
+    } else {
+        //output mono:
+        //then we need to mix the two buffers into buf
+        for(i=0;i<samples;i++) {
+            int sample = (int)mixbuf0[i] + (int)mixbuf1[i];
+            if (unlikely (sample > 32767)) {
+                sample = 32767;
+            }
+            else if (unlikely (sample < -32768)) {
+                sample = -32768;
+            }
+            outbuf[i] = (short)sample;
+        }
+    }
     break;
   }
 
   //now reduce to 8bit if we need to
-  if(!use16bit)
-    for(i=0;i<(stereo ? samples*2 : samples);i++)
-      ((char *)buf)[i] = (outbuf[i] >> 8) ^ 0x80;
+  if(unlikely (!use16bit)) {
+      int smp = stereo ? samples*2 : samples;
+      for(i=0;i<smp;i++) {
+          ((char *)buf)[i] = (outbuf[i] >> 8) ^ 0x80;
+      }
+  }
 }
 
 void CEmuopl::write(int reg, int val)
 {
   switch(currType){
-  case TYPE_OPL2:
   case TYPE_DUAL_OPL2:
-    OPLWrite(opl[currChip], 0, reg);
-    OPLWrite(opl[currChip], 1, val);
+    OPLWrite(opl[1], 0, reg);
+    OPLWrite(opl[1], 1, val);
+  case TYPE_OPL2:
+    OPLWrite(opl[0], 0, reg);
+    OPLWrite(opl[0], 1, val);
     break;
   case TYPE_OPL3:	// unsupported
     break;